The invention concerns a process for manufacturing natural stone-type, panel-shaped construction and decoration materials of high solidity for facing facades, walls and floors in indoor and outdoor areas, comprising stacked individual layers of crushed glass, charge material, in particular sand, and mixtures thereof.
A great variety of natural and synthetic materials are used for decorative applications in indoor and outdoor areas. Of the natural materials, in particular marble and granite find broad application and are used in large quantities for the interior and exterior facing of representative buildings. In addition to the decorative impression, corrosion resistance and economic production of the materials must also be ensured. Materials which occur naturally do not always meet these requirements, since sufficiently large surfaces of homogenous appearance can often not be obtained and since the corrosion resistance and solidity are not always optimal, due to the porosity of the natural material.
A glass ceramic material is thus known from DE 41 25 698 C1, having the following composition (in wt. % on oxide basis):
______________________________________ SiO.sub.2 64.1-72 Al.sub.2 O.sub.3 2.9-11 CaO 15.0-26 MgO 0-8 ZnO 0.ltoreq.2 BaO 0-0.5 K.sub.2 O 0-7.4 Na.sub.2 O 0-2 F 0.5-4 ______________________________________
whereby .SIGMA. Na.sub.2 O+K.sub.2 O is at least 2.
This material is used in the construction industry as a natural stone substitute for decorative applications, to cover floors and to face walls and facades.
Glass ceramic as a natural stone substitute offers a good decorative appearance, but is costly and difficult to produce, due to, e.g., the expensive ceramization process. In addition, relatively pure and thus valuable raw materials are needed to manufacture this material.
DE 41 23 581 A1 discloses a process for manufacturing form bodies, in particular construction panels, from glass granulates, wherein raw granular material is made from a mixture of crushed glass and a foaming agent and said raw granular material can be expanded under heat, whereby
first, a layer of unexpanded raw granules and, thereabove, a layer of expanded foam glass granules are deposited in a mold in a hot or cold state as feed, PA1 the feed is then heated to 700.degree. to 900.degree. C., preferably 800.degree. to 900.degree. C. PA1 and subsequently compressed under a pressure of 0.005 to 0.015N/mm.sup.2 by 5 to 15%, whereby a form body of firm compound arrangement is created. PA1 the panels do not react with the production mold, PA1 no unevennesses occur on the panel surface, PA1 the panels are not subject to deformation, PA1 no bubbles, pores, occlusions and/or microcracks are formed in the top layer and PA1 there is no need for grinding or polishing of the final product. PA1 1.1 optionally depositing a level, evenly thick layer of sand in at least one temperature-resistant mold; PA1 1.2 deposition of a level, evenly thick layer of a mixture of crushed glass and sand on top of said layer of sand if the latter is present; PA1 1.3 super-deposition of a further level layer of crushed glass; PA1 1.4 whereby each individual layer is compressed and the entire resultant layer stack is compressed; PA1 1.5 subsequently heating the layer stack in the at least one mold to a temperature of 600.degree.-850.degree. C. during a period of 20-100 min.; PA1 1.6 tempering the heated layer stack at 600.degree.-850.degree. C. for a period of 6-35 min.; PA1 1.7 subsequently further heating the layer stack to a temperature at which the surface of the glass displays a viscosity .eta. of 10.sup.4 to 10.sup.5.5 dPas and maintaining this temperature for 6-40 min., whereby the temperature application occurs unilaterally from above by a heat flow evenly distributed across the panel surface; PA1 1.8 cooling the layer stack to a temperature of 600.degree.-750.degree. C. over a period of time sufficient to obtain an even temperature distribution through the volume of the layer stack; and PA1 1.9 maintaining the temperature of 600.degree.-750.degree. C. for 15-65 min., followed by precise linear cooling to a temperature of 400.degree.-500.degree. C. at 2-5K/min. and, upon reaching this temperature, performing free or forced cooling to room temperature. PA1 0-30 mm, in particular 1.5-2 mm for the sand layer (1.1, i.e., the first layer); PA1 2-30 mm, in particular 12-15 mm for the mixture layer (1.2, i.e., the middle layer); PA1 2-7 mm, in particular 3-5 mm for the glass layer (1.3, i.e., the upper or surface layer).
These construction panels manufactured by the process according to the DE 41 23 581 A1 are particularly suited for use as insulation panels in a thermal insulation compound system, whereby the raw granular material of which the panels are composed must first be manufactured with great expenditure of energy.